1. Field of the Invention
The invention relates to an electrochemical storage battery, especially of the alkali metal-and sulfur type, with at least one storage cell and at least one heat insulation surrounding the storage cell.
2. Description of the Prior Art
Electrochemical storage batteries which operate at elevated temperatures, a temperature higher than 100.degree. C. and above the ambient temperature, are usually surrounded by a heat-retarding insulation in order to prevent the storage cells from cooling down below the minimum temperature necessary for their operation. Conventional insulation, which is built up, for instance, from glass wool or mineral wool must have considerable wall thickness to have sufficient insulating effect. This is especially true if the storage battery operates at elevated temperatures, e.g., 300.degree. C., and is to be held at approximately constant temperature over extended periods of time, e.g., hours. Since such thick-walled heat insulation increases the dimensions and/or the weight of the storage battery considerably, the energy storage density, i.e., the electric energy that can be stored per unit weight or volume, is small. This is a disadvantage especially for such electrochemical storage batteries which are to be used as power supply for electrically operated vehicles.